r/.in. 



-.,;^^^^rr..r7.,^.,,f^^n;ii;:w.yz !''^^ 



CJ. H 



Fi(!. 165. — Tkansvekse Sections of the Nose in various Vertebrates. 

 A — U, Illustrating the various ontogenetic and phylogenetic stages of the Jacob- 

 son's organ of Urodeles. In A its position is median, and in D lateral. 



E, Gymnophiona, in wliich the organ becomes separated from the main nasal cavity. 



F, Lacerta agilis. 



G, Placental Mammal ; I, the same, in longitudinal vertical section. 

 H, Ornilhorhj-nchus. (After Symington. ) 



jV, main nasal cavity ; jc, Jacobson's organ ; c.j, Jacobson s cartilage ; g.m, 

 intermaxillary gland ; g.n, nasal gland ; n.o, olfactorj' nerve ; n.t, trigeminal 

 nerve ; <J.ii, naso-lachrymal duct; m.v, maxilla ; o.rJ, dumb-bell shaped bone. 



